We recently had a highly modified Toyota GR Yaris in the Whifbitz workshop for a series of upgrades and to resolve a few underlying issues.

The car had already undergone extensive modifications by another company, and initially, our task was simply to remap the ECU. However, once we got it on the dyno, it became clear there were some mechanical problems that needed attention before tuning could proceed. When we attempted to increase the boost, we discovered that the cylinder head wasn’t sealing correctly. A teardown revealed that a standard Toyota head gasket had been used — clearly not up to the task.

With the engine apart, we took the opportunity to port the cylinder head and install Supertech valves. The rebuild included an Athena head gasket paired with stronger DP head studs to ensure proper sealing under high boost. During our initial tuning attempts, we also traced a boost leak to a split wastegate diaphragm, which was promptly replaced.

To further enhance performance, we upgraded the intercooler to a Wagner Tuning unit with larger pipework, and added a Turbosmart Raceport blow-off valve.

Back on the dyno, the results were impressive — the Yaris produced 600bhp at 2.5 bar of boost on E85 fuel. The setup is now fully mapped with switchable boost levels (low, medium, and high) controlled conveniently from the steering wheel. The dyno graph below shows the power at the wheels.

Spec of this beast below:

Syvecs GR Yaris ecu
Garage Whifbitz CNC ported cylinder head
Garage Whifbitz carbon engine cover
Garage Whifbitz carbon cooling panel
Athena head gasket
Kelford G16E-GTS 276/286 billet camshafts
Kelford G16E-GTS valve springs
IRP forged pistons
IRP conrods
DP L19 head stud kit
Stainless steel exhaust system
Lamspeed Racing G16E-GTS turbo kit with a Garrett G25-660 turbo, Turbosmart external wastegate, 3″ downpipe and midpipe
Wagner Tuning intercooler kit
Lamspeed Racing billet intake manifold
Eventuri intake kit
HKS Iridium spark plugs
Airtec Motorsport catch tank
Airtec Motorsport engine oil cooler
Airtec Motorsport catch tank
Garage Whifbitz fuel system comprising of a Radium boot mounted surge tank, Walbro 525lph fuel pump, flex fuel sensor and teflon braided hoses throughout
Deutworks 1100cc upgraded port injectors
Lamspeed Racing baffled sump kit